Air cylinder



FIG. 1 is a top, front and left side perspective view of air cylinder embodying my new design;

FIG. 2 is a bottom, rear and right side perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a left side elevational view thereof;

FIG. 7 is a right side elevational view thereof; and,

FIG. 8 is a cross-sectional view thereof taken along line 8--8. 

The ornamental design for air cylinder, as shown and described. 